Conveyor belts have long been known as effective means for transporting parcels, articles or objects. A conveyor belt can be used to move objects, such as parcels or parts, through a sorting facility, a manufacturing plant or an assembly plant.
Often, a conveyor belt must transport articles around a curve. For example, it is not uncommon for two straight runs of a conveyor belt to sit adjacent one another or to be perpendicularly oriented to form a ninety degree (90.degree. ) angle. A curved section of the conveyor belt must transport articles from the end of the first conveyor belt to the start of the second conveyor belt.
There are numerous patents relating to powered belt turns in conveyor belt systems. For example, in U.S. Pat. No. 3,951,256, issued to Gurewitz, an endless, arcuate shaped conveyor belt carries articles around curves in a conveyor belt system. The arcuate conveyor belt is hung between two rollers. A motor powers one of the rollers, which roller causes the arcuate belt to rotate. One of the two rollers is positioned adjacent the feed conveyor belt and the other roller is positioned adjacent the exit conveyor belt. A bed supports the arcuate conveyor belt. Rotation of the arcuate conveyor belt carries objects between the feed conveyor belt and exit conveyor belt. Guides on the rollers keep the arcuate conveyor belt on-line on the bed and rollers.
Another powered belt turn is set forth in U.S. Pat. No. 3,153,475, issued to Swanson. In Swanson, a ring-shaped conveyor belt is mounted on rollers. The conveyor belt is folded in half and the rollers are positioned within the belt along the folded radius of the ring-shaped conveyor belt (FIG. 1). Each roller has a gear mechanism that extends into the opening in the center of the ting-shaped conveyor belt. A central shalt with gears engages both rollers, thereby causing both rollers to turn. The rotational movement of the rollers causes the conveyor belt to rotate, thereby transferring objects on the upper surface of the conveyor belt around a one hundred and eighty degree (180.degree. )turn.
The provision of powered belt turns such as those discussed above require positioning and maintaining the conveyor belt on end rollers. For example, guide chains mounted on one or both sides of the conveyor belt, or flanges and corresponding apertures on the rollers and conveyor belt, must be present in the powered belt turn to keep the conveyor belt in position around the curved path. These guide devices are complicated, expensive and have been found to wear rapidly, requiring frequent adjustment or part replacement.
Therefore, it would be desirable to have a powered belt turn that requires no guide means or means for keeping the curved conveyor belt on an arcuate path.
Furthermore, there is a need for a curved conveyor belt that can be operated at very high speeds without fear of the conveyor belt being disconnected from the guide means or the drive means.